During our kernel version migration we encountered an issue preventing DPC
from being used by the kernel on the downstream ports of PCIe switches.
After some review of the patch history & code we found that the kernel
now required pcie_ports=dpc-native command line argument for such devices.
This came after we picked up:
"PCI/portdrv: Allow AER service only for Root Ports & RCECs"
Belief is that the above patch is 'more correct' on the AER side, but perhaps
'less correct' on DPC. I initially reached out in the patch's email
thread to see whether others had thoughts & whether this change might be
desireable after which I was asked if I would submit a patch. Took a little
time to read some of the ACPI/PCIe specifications which are the basis of my
beliefs about the correctness of this patch. That being, if a user builds the
kernel with DPC/AER & the kernel receives OS control over AER, then it should
automatically use AER & DPC where applicable in the PCIe hierarchy.
Matthew W Carlis (1):
PCI/portdrv: Allow DPC if the OS controls AER natively.
drivers/pci/pcie/portdrv.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
base-commit: ceb6a6f023fd3e8b07761ed900352ef574010bcb
--
2.17.1
